PRELIMINARY
ICS840004-11
Integrated
Circuit
Systems, Inc.
FEMTOCLOCKS™ CRYSTAL-TO-
LVCMOS/LVTTL FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
FEATURES
• Four LVCMOS/LVTTL outputs, 15Ω typical output imped-
The ICS840004-11 is a 4 output LVCMOS/
ICS
HiPerClockS™
ance
LVTTL Synthesizer optimized to generate
Ethernet reference clock frequencies and is a
member of the HiPerClocksTM family of high
performance clock solutions from ICS. Using a
• Crystal oscillator interface
• Input frequency range: 22.4MHz to 28MHz
• Output frequency Range: 56MHz - 140MHz
• VCO Range: 560MHz - 700MHz
25MHz, 18pF parallel resonant crystal, 125MHz and
62.5MHz can be generated based on one frequency select
pin (F_SEL). The ICS840004-11 uses ICS’ 3rd generation low
phase noise VCO technology and can achieve 1ps or lower
typical random rms phase jitter, easily meeting Ethernet jitter
requirements. The ICS840004-11 is packaged in a small
20-pin TSSOP package.
• RMS phase jitter at 125MHz (1.875MHz - 20MHz):
0.70ps (typical)
• RMS phase noise at 125MHz:
• Full 3.3V supply
• 0°C to 70°C ambient operating temperature
• Available in both standard and lead-free RoHS-compliant
packages
FREQUENCY SELECT FUNCTION TABLE FOR ETHERNET FREQUENCIES
Inputs
M Divider N Divider
Output Frequency
(25MHz Ref.)
M/N
Ratio Value
F_SEL
Value
Value
0
1
25
10
2.5
62.5
125
25
5
5
BLOCK DIAGRAM
PIN ASSIGNMENT
F_SEL
nc
nc
1
20
19
18
17
16
15
14
13
12
11
GND
Q0
Q1
VDDO
Q2
Q3
GND
XTAL_IN
XTAL_OUT
2
3
4
5
6
7
8
9
Pullup
OE
nc
nc
OE
nc
nc
VDDA
nc
VDD
Pullup
F_SEL
F_SEL
N
25MHz
XTAL_IN
Q0
Q1
Phase
Detector
0
1
÷10
VCO
OSC
÷5
10
XTAL_OUT
ICS840004-11
Q2
Q3
20-LeadTSSOP
M = ÷25 (fixed)
6.5mm x 4.4mm x 0.92mm
package body
G Package
Top View
The Preliminary Information presented herein represents a product in prototyping or pre-production. The noted characteristics are based on
initial product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications
without notice.
840004AG-11
www.icst.com/products/hiperclocks.html
REV.A OCTOBER 3, 2005
1